In general, a vacuum cleaner sucks dust or small filth with air and accumulates them in a dust bag. But, such a vacuum cleaner is uneconomical and unsanitary since a dust bag has to be frequently changed and a user has to touch the bag whenever changing it.
Therefore, when accumulating dust or small filth, a cyclone type vacuum cleaner developed to solve such problems accumulates heavy filth first in a dust container made of a transparent material by rotation of sucked air using a centrifugal force. Accordingly, a user can see with the naked eye how much dust or filth are accumulated therein and thus can throw away the dust when a certain amount of dust is accumulated therein. Besides, the dust container is semipermanent. Since the cyclone type vacuum cleaner is economical and sanitary as described, researches therefore are actively ongoing.
FIG. 1 is a sectional view of a general cyclone type vacuum cleaner.
A conventional cyclone type vacuum cleaner includes a cleaner main body 106 to which a dust separator 104 in which dust is collected by a cyclone method is attached, and a suction head 108 mounted at a lower portion of the cleaner main body 106, for sucking dust from a floor.
The cleaner main body 106 is erectly disposed, a knob which a user grabs in order to perform a cleaning operation is mounted at an upper portion of the cleaner main body 106, and a blower 130 driven when power is applied thereto, for generating a suction force for sucking dust is mounted in the cleaner main body 106.
At a lower portion of the suction head 108, there is formed a suction opening 110 into which dust is sucked and a moving wheel 112 for moving the cleaner is mounted. Also, a brush 114 for sweeping up the dust on a floor is rotatably mounted at the suction opening 110.
The suction opening 110 of the suction head 108 is connected to the dust separator 104 by a suction pipe 116 so that the dust sucked through the suction opening 110 is collected in the dust separator 104 through the suction pipe 116.
FIG. 2 is a sectional view of a dust separator in accordance with the conventional art.
A conventional dust separator 104 includes: a hopper 150 connected to the suction pipe 116 and having a certain eddy space, for separating the dust from air; a collecting container 152 in which the dust separated in the hopper 150 is collected; and an air discharge pipe 154 connected to an upper portion of the hopper 152 and through which air separated from the dust is discharged to the outside.                an inner diameter of the hopper 150 becomes narrower toward a lower portion thereof. The suction pipe 116 is eccentrically connected to an upper portion of the hopper 150 in order to generate an whirl in the hopper 150, and the air discharge pipe 154 is inserted in the upper portion of the hopper 150 in certain degree.        
Herein, the air discharge pipe 154 is connected to the blower 130 to discharge air.
An operation of the dust separator of the conventional cyclone type vacuum cleaner constructed as above will now be described.
When the blower 130 is driven and thus a suction force is generated, dust on a floor is sucked through the suction opening 110 and then is sucked into the hopper 150 through the suction pipe 116. Air containing the dust sucked into the hopper 150 is rotated in the hopper 150 to thereby separate the dust from air by a centrifugal force. Then, the dust falls in a lower direction and thus is collected in the connecting container 152, and the air separated from the dust is discharged to the outside through the air discharge pipe 154.
However, the cyclone type vacuum cleaner in accordance with the conventional art has following problems.
When the dust and air is separated from each other in the hopper 150 by a centrifugation, fine dust in the air cannot be separated and is included in the air discharged to the outside through the air discharge pipe 154. Accordingly, an efficiency of collecting dust is deteriorated.
In order to solve this problem, if a filter for filtering the dust is installed at the air discharge pipe 154 for discharging air, the efficiency of collecting dust can be improved, but a suction force for sucking dust on a floor is deteriorated by the filter.